Used printer cartridges of fax machines, copiers, inkjet printers, and laser printers are often remanufactured. Printer cartridges typically include a toner hopper, a waste hopper, primary charge roller or PCR, a developer roller, and a drum. The drum is usually one of the components that wears out from usage and gets replaced during remanufacturing. The drum is typically attached to a drum axle, which is connected to a motor of the printer and allows the motor to rotate the drum. In some cartridges, the drum is attached to the drum axle with a mechanical spring pin that is inserted through a plastic cap portion of the drum and a portion of the drum axle. Examples of these cartridges include cartridges for Hewlett-Packard laser printer model numbers 3000, 3500, 3600, 3700, and 3800.
In addition to the mechanical spring pin attaching the drum to the drum axle, in some cartridges, a spring pin also attaches the drum axle to a drive element. The spring pin is also inserted through the drive element and a portion of the drum axle. The drive element of the printer cartridge is configured to fit to a drum drive gear of a printer to allow the printer to rotate the drum axle and the drum. Examples of these cartridges include cartridges for Hewlett-Packard laser printer model number 4700.
To detach the printer cartridge components joined by the spring pin, a hammer and a chisel is conventionally used. For instance, the chisel is first aligned with the mechanical spring pin. Once the chisel is aligned, a hammer is used to cause the chisel to drive the mechanical spring pin until it no longer holds the printer cartridge components. Other conventional methods include using a punch in lieu of the chisel. The punch may include a flatter head than the chisel, which provides a wider surface of pin contact than the chisel. Consequently, the punch may more effectively contact and drive the mechanical spring pin.
At least one problem with the conventional methods and tools is that they expose the drum to being damaged. For instance, the drum may include drum caps made of soft plastic. Since irregular force is applied to the drum cap by the hammer, the chisel, or the punch, the soft plastic of the drum cap may be deformed. Conventional tools may also damage the mechanical spring pin. Another problem with the conventional tools is that they may be difficult to use. The chisel or the punch may contact the mechanical spring pin, but may easily slip from the mechanical spring pin. Thus, the conventional methods and tools may not be desirable in high volume cartridge remanufacturing environments. Methods and apparatus for efficiently and quickly detaching and reattaching printer cartridge components joined by a spring pin are desired and are addressed by the present invention.